The biggest polluter in Illinois is a huge coal power plant owned by a Texas utility Dynegy. The Baldwin Plant alone pollutes 12 million tons of carbon (out of a statewide total of 91 million). Most of the 91 million is from coal power plants. And we don't charge them anything for that pollution.

The market price for a ton of carbon pollution is apparently about $12/ton. If Illinois decided to quit subsidizing these polluters and had them pay the market price for their pollution, we'd generate more than a billion dollars -- annually. (91 million tons times $12/ton).

To put that in context, all the debate over lowering the state income tax from 5% to 3.75% will cost about $3 billion. We could lower the income tax even more down to 3.25% with the money we could raise from charging polluters a market price.

Thanks to the feds compiling this data (which is only about half the total carbon emissions), we're in a place to sketch out what a fee on carbon pollution might actually generate. That's very helpful.